A miniature silicon accelerometer with built-in damping

Silicon micromachining was utilized to produce a novel, miniature accelerometer comprising a three-layer silicon structure. The center layer contains the accelerometer proof mass supported by a double cantilever suspension. The outside two silicon caps provide protection, mechanical stops for the proof mass, and air damping of its major resonant frequencies. Critical damping is typically provided. Piezoresistors are used to sense the deflection of the silicon mass. By cross coupling the eight resistors in a Wheatstone bridge, substantial reduction in sensitivity to off-axis acceleration has been achieved. The integral packaging and air damping reduces production costs by simplifying the final assembly steps.<>